Re: BYTEA - Mailing list pgsql-sql

Andreas Joseph Krogh schrieb am 17.01.2016 um 23:09:
>      > Do I  really *Need to escape/encode binary data before sending to DB
>      > then do the reverse after retrieving the data?*
>      > *
>      > *
>      > If so, what (*Java*) codes should I use to achieve this goal (I am using
>      > the Java to interface with the DB)?
>
>     https://jdbc.postgresql.org/documentation/94/binary-data.html
>
> Save yourself the trouble and don't go this route. Use https://github.com/impossibl/pgjdbc-ng instead.

Can you elaborate?

Using the "official" JDBC driver with bytea column works just fine for me.

Using BLOBs (that is SQL-BLOB, not *ps.setBinaryStream etc.) with ps.setBlob/rs.getBlob and Connection.createBlob certainly doesn't work using the official driver.

 

https://github.com/pgjdbc/pgjdbc/blob/master/pgjdbc/src/main/java/org/postgresql/jdbc/PgConnection.java#L1284-L1287

 

  public Blob createBlob() throws SQLException {    checkClosed();    throw org.postgresql.Driver.notImplemented(this.getClass(), "createBlob()");  }

 

AFAIU this thread is about working with LARGE OBJECTS, not only binary data.

Also, using BYTEA with LARGE objects (not just binary data) quickly leads to OutOfMemoryError. Which is why I recommend using pgjdbc-ng and real BLOBs (using OID) instead. It is true that get/setBinaryStream "works", in essence that it appears to do the jobb. The problem is that despite using get/setBinaryStream with BYTEA appears to use streams, it doesn't, and the whole byte-array is kept in memory, both in the JAVA-app and in PG. The only way to work with real streams all the way is using OID, not BYTEA.

 

But, of course, if you only work with small-ish binary data, yes - BYTEA does the job.

 

--

Andreas Joseph Krogh

CTO / Partner - Visena AS

Mobile: +47 909 56 963

andreas@visena.com

www.visena.com